Final Remediation of Post-Biological Treated Milk Whey Wastewater by Ozone

Abstract

This work deals with a real environmental problem related with milk whey wastewater. Even if a high depuration degree can be achieved using aerobic biological processes, the final effluent does not accomplish the legal regulation for disposal. In this context, we studied the application of ozone oxidation after an activated sludge treatment in order to obtain an effluent suitable to be discharged into the natural water courses. Even if the pH increase improved single ozonation efficiency, the treated wastewater was not yet able to be disposed of. The introduction of hydrogen peroxide at low concentrations enhanced the ozone action over the pollutants, and this combination led to residual water within the environmental law conditions to be released on the surroundings. Furthermore, heterogeneous catalytic ozonation over Mn-Ce-O 70/30 (prepared in our laboratory) and the commercial N-150 catalyst (Fe2O3-MnOx) was very efficient on the wastewater depuration. Nevertheless, the high amount of carbon adsorbed on the recovered catalysts disable the industrial implementation of this technology.